Overview
Newell’s Shearwater (Puffinus newelli), known in the Hawaiian language as ‘A’o’ after its donkey-like braying nocturnal call, is an elusive, critically endangered pelagic seabird endemic to the Hawaiian archipelago. Spending months skimming low over the open equatorial Pacific Ocean, it returns to land only under cover of deep night to breed in isolated burrows dug into nearly vertical, cloud-draped mountain rainforest cliffs. Its drastic population decline over recent decades highlights the complex conservation challenges facing oceanic island ecosystems.
Biology and Physical Characteristics
Puffinus newelli features high-contrast countershaded plumage: its crown, back, wings, and tail are a glossy sooty-black, sharply juxtaposed against a clean white throat, breast, belly, and undertail coverts. A conspicuous white patch extends up the sides of its rump. Its long, narrow, stiff wings are built for dynamic soaring across ocean swells with minimal flapping. The bill is dark, slender, and hooked with external tubular nostrils (tubinares) specialized for expelling concentrated dietary sea salt and detecting airborne scent plumes of marine prey.
Behavior and Ecology
Newell’s Shearwaters spend the non-breeding season far out at sea across the central tropical Pacific, diving up to thirty feet underwater to pursue squid and small fish associated with tuna schools. Between April and November, adults fly inland after sunset, navigating up misty mountain valleys to nest in subterranean burrows sheltered beneath dense uluhe ferns. Both parents share incubation of their single white egg. Fledglings take their maiden flight in autumn, guided by the stars toward the safety of the open sea.
Conservation and Human Impact
The Newell’s Shearwater population plummeted by over 75 percent between 1993 and 2008, driving it to Critically Endangered status. Its most severe hazard is light pollution: young fledglings become disoriented by coastal stadium lights, streetlamps, and resorts, circling until exhausted and crashing to the ground (‘seabird fallout’), where they are killed by vehicles or introduced feral cats, rats, and pigs. Intensive recovery programs on Kauai include nocturnal lighting shields, predator-proof fenced reserves, and community-led rescue stations.
Interesting Factoid
The Hawaiian name for this bird, ‘A’o’, perfectly mimics its strange, nocturnal courtship call echoing from mist-covered mountain peaks, which sounds remarkably like a braying donkey.
Last updated: October 2026